There are currently two general classes of methods used to create channels through an occlusion, for example an occlusion located in a blood vessel of a patient.
The first class of methods uses a guide wire mechanically pushed through the occlusion. A major disadvantage of such methods resides in that the wire dimensions, and hence the wire rigidity, is limited by the dimensions of the vessels though which the wire must be inserted to reach the occlusion and by currently available materials. Therefore, it often occurs that a specific occlusion has a portion that is too hard to allow pushing the wire therethrough.
For example, many occlusions located in blood vessels include a calcified or fibrous cap at the ends thereof, the cap being in some cases too hard to allow penetration by the wire. The remaining portions of the occlusions are typically relatively soft and are relatively easily penetrated by existing mechanical guide-wires.
In another class of methods, energy, for example radio-frequency energy, is delivered into the occlusion and a device delivering the energy is advanced through a channel thereby created. However, applying energy, while allowing to go through relatively hard occlusions, is often risky as the energy may vaporize or liquefy the wall of the blood vessel, which may thereby be injured and cause complications that require an emergency surgery, or even death.
Due to this risk, many devices that utilize energy to go through an occlusion include means for ensuring that the energy is not delivered through the vessel wall. For example, an optical sensor is used to acquire information related to the composition of the tissue into which the energy is provided. If the tissue is determined not to be a tissue through which the channel should be created, the delivery of energy is stopped. However, such devices are relatively complex, relatively expensive, relatively complex to operate and relatively large, which make them impractical or unsuitable for many interventions.
In addition, many currently existing devices used to create channels within the body have a substantially fixed shape, for example a substantially curved or a substantially rectilinear shape, when no external force is applied on the device. These devices are therefore relatively hard to direct to create channels having a predetermined shape. Also, these devices may be difficult to advance in a desired direction when reaching bends or bifurcations within the body vessels.
Current devices are intended to use either radiofrequency or mechanical energy to traverse occlusions in their entirety. Such devices would typically not be used to provide both functionalities due to, for example, the size, shape and/or other properties of the devices. For example, standard mechanical guide-wires are not structured to for delivery of electrical energy and current radio-frequency devices are typically not suitable for mechanical perforation. In addition, many clinicians may avoid using current radio-frequency devices to traverse occlusions due to the fact that they prefer the ‘feel’ of a standard guide-wire, such as those they've used previously for such procedures.
Against this background, there exists a need in the industry to provide novel methods and apparatuses for creating a channel through an occlusion. An object of the present invention is therefore to provide such a method and an apparatus.